1. Field of the Invention
The present invention relates generally to a cyclone dust collector making use of cyclone action and, more particularly, to a vacuum cleaner provided with the cyclone dust collector.
2. Discussion of the Related Art
Among the cyclone dust collectors, a duel type cyclone dust collector comprising a primary cyclone dust collector 1 and a secondary cyclone dust collector is configured to perform iterative collection of foreign matters more effectively than a single cyclone dust collector.
FIGS. 1 to 3 illustrate an application of the above-stated dual type cyclone dust collector to an upright type vacuum cleaner. The upright vacuum cleaner has a dual type cyclone dust cleaner including primary and secondary cyclone dust collectors 1 and 2 provided in a cleaner body, a fan 3 provided at the bottom in the cleaner body for generating the suction force, and a fan motor 4 for driving the fan 3.
The dual type cyclone dust collector operates by driving the fan motor 4 to rotate the fan 3, which generates a suction force. Thus a variety of foreign matters as well as air in the room are sucked into the dual type cyclone dust collector and introduced into an exterior body 1a via the primary cyclone dust collector 1 and a first air inlet passage 1b. The air and fine dust introduced into the exterior body 1a pass through a first air outlet passage 1c and then a second air inlet passage 2b due to the suction force and then enter an interior body 2a. In the meantime, relatively large dust particles cannot enter through holes formed on the circumferential surface of the first air outlet passage 1c and gather at the bottom in the exterior body 1a due to their weight
As shown in FIG. 2, the air and the fine dust introduced into the interior body 2a are subjected to a centrifugal force during entrance to the interior body 2a This force results from the second air inlet passage 2b extending in a tangential direction with respect to the circumference of the interior body 2a Thus the air and the fine dust rotating along the inside of the interior body 2a are separated from each other due to a difference in the centrifugal force. Relatively heavy-weighted fine dust falls down along the inside wall of the interior body 2a due to their weight and gather in a dust collecting section 2d, and the air escapes interior body 2a via a second air outlet passage 2c though an ascending air current formed at the center of the cyclone inside of the interior body 2a. 
A partition plate 2e is provided to separate the dust collecting section 2d from the dust collection section of the exterior body 1a so that the foreign matter collected in the exterior body 1a and interior body 2a are kept separate.
The secondary cyclone dust collector 2 of the above stated dual cyclone dust collector may be configured to collect fine dust. Nevertheless, it is still possible that relatively light-weighted fine dust may pass through the second air outlet pass to the fan 3 and the fan motor 4. This is because the secondary cyclone dust collector 2 collects foreign matters using the cyclone effect in the same manner as the primary cyclone dust collector 1. Therefore, fine dust unable to be separated from the air using the cyclone effect will pass along with the air to the fan 3 and fan motor 4. The primary cyclone dust collector 1 solely collects relatively large dust, while the fine dust continues to enter the secondary cyclone dust collector 2, which may have a dust capacity that is too small so that the user must discard the foreign matters collected in the secondary cyclone dust collector 2 in order to prevent damage to the fan motor 4.
To solve the above problem, the primary cyclone dust collector 1 has to have a large-sized exterior body, which is why the dual type cyclone dust collector has been applied only to upright type vacuum cleaners. In other words, the above-described dual cyclone dust collector has such a low dust capacity that it cannot be applied to a canister type vacuum cleaner thereby inconveniencing users.